Attempt to Protect Wood Colour Against UV/Visible Light by Using Antioxidants Bearing Isocyanate Groups and Grafted to the Material with Microwave

Grelier, Stéphane; Castellan, Alain; Desrousseaux, Stéphanie; Nourmamode, Aziz; Podgorski, L.

doi:10.1515/hfsg.1997.51.6.511

Cited by 31 publications

(15 citation statements)

References 13 publications

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“…26 The 1 H and 13 C NMR spectra of compound 1 confirm its structure. 26 The synthesis of 3 (Scheme 1) needed the preparation of 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl radical.…”

Section: Synthesis Of 1 and 3 Derivativesmentioning

confidence: 76%

“…26 The 1 H and 13 C NMR spectra of compound 1 confirm its structure. 26 The synthesis of 3 (Scheme 1) needed the preparation of 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl radical. 34 Oxone (36.6 g, 59.5 mmol) in water (200 mL) was added dropwise to a mixture of 2,2,6,6-tetramethylpiperidine-1,4-diol (Aldrich, 3.96 g, 25.2 mmol), acetone (10 mL) and phosphate buffer (Aldrich, 50 mL).…”

Section: Synthesis Of 1 and 3 Derivativesmentioning

confidence: 76%

“…17,26,30 The grafting does not modify in a large extent the color coordinates of SCB fibers (Figure 1a), whereas those of PB-SCB are more affected, especially the luminance L* when UV absorber is grafted (Figure 1b). It is likely that the bleaching changes the surface of the fibers and during the condensation of the isocyanate group, this surface is modified again, affecting the scattering of the fibers, which contributes to the luminance.…”

Section: Photocoloration Of Fibers After Grafting Of Uv-absorber And/mentioning

confidence: 99%

“…The fibers were washed several times with acetone (5×50 mL) and dried for 4 h, at 80 °C. This procedure was shown to be appropriate to graft UV-absorber and HALS isocyanates onto lignocellulosic materials, 26 despite no evidence of the grafting was obtained by FTIR or CP-MAS NMR spectroscopies. The grafting procedure was repeated to obtain at about 1% (m/m) grafting, 2.…”

Section: Grafting Of 1 and 3 Derivatives Onto Bagasse Fibersmentioning

confidence: 99%

“…23,24 For clear woods, the combined action of hydroxybenzophenone or hydroxyphenylbenzotriazole UV absorbers and antioxidants such as hindered amine light stabilizers (HALS) or polyethylene glycols is quite efficient, 25 especially when the additives are grafted at the wood surface. 26 Titanium, zirconium, manganese, chromium, iron or copper derivatives confer some photoprotection to wood. 27,28 Polyester binders containing benzotriazole and HALS or waterbased UVcured polyurethane-acrylate coating were also developed for the same goal.…”

Section: Introductionmentioning

confidence: 99%

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Photodegradation of sugarcane bagasse fibers: influence of acetylation or grafting UV-absorber and/or hindered nitroxide radical on their photostability

Ruggiero

Machado

Hoareau

et al. 2006

J. Braz. Chem. Soc.

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um radical nitróxido do tipo piperidiniloxi (3). As fibras FBC-AP foram também acetiladas com anidrido acético. A fotossensibilidade dessas fibras à radiação UV foi avaliada comparativamente, empregando coordenadas Lab color, assim como pela monitoração dos seus espectros de reflectância difusa no UV-Visível. As fibras FBC mostraram-se fotoestáveis, enquanto que as FBC-AP apresentaram certa sensibilidade à radiação UV. A estabilidade das FBC deve-se à presença de unidades do composto fotoestável p-hidroxifenilpropano, proveniente dos fragmentos de lignina. As fibras FBC enxertadas e não-enxertadas apresentam comportamentos similares frente à radiação UV e Visível enquanto que as FBC-AP enxertadas são fotoestabilizadas pela presença de 2 ou 4, ou ambos. A acetilação das fibras FBC-AP induz a fotoestabilização, em adição a certo efeito de fotoalvejamento. O fotoalvejamento foi também apresentado por medidas de emissão de fluorescência. Como conseqüência dessas observações, as fibras FBC devem ser consideradas como materiais lignocelulósicos com elevado potencial de aplicação em ambientes externos.Unbleached (SCB) and peroxide bleached (PB-SCB) sugarcane bagasse fibers were grafted with hydroxyphenylbenzotriazole UV absorber (1) and/or hindered nitroxide radical of piperidinyloxy type (3). PB-SCB fibers were also acetylated with acetic anhydride. The photosensitivity of the various fibers to UV light was comparatively evaluated using Lab color coordinates and by monitoring their UV-Visible diffuse reflectance spectra. SCB fibers were found to be photostable whereas PB-SCB fibers presented some sensitivity to UV light. The stability of SCB fibers was attributed to the presence of photostable para-hydroxyphenylpropane units in SCB lignin. The grafted and non-grafted SCB fibers showed similar behaviors against UV-Visible light whereas grafted PB-SCB were photostabilized by the presence of 2 or 4 or both. Acetylation of PB-SCB fibers induced photostabilization in addition to some photobleaching effect. The photobleaching was also revealed by fluorescence emission studies. As a consequence of these observations, SCB fibers might be considered to have a high potential for lignocellulosic materials to be used outdoors. Keywords: bagasse fibers, photodegradation, photoprotection IntroductionFibers obtained from biomass are cheap, non-toxic and easily recyclable. Their use contributes to environmental protection.1 Among them, sugarcane bagasse is a poorly valorized waste residue from sugar and alcohol industries.It is usually burnt for energy supply. Valorization of this material includes pulps, 2 thermoset composites, 3 outdoor usages, 4 cement strengtheners 5 and materials for cleaning water from heavy metal contaminants. 6 Another important research field involving this material is its bioconversion to produce protein rich animal aliment, enzymes, amino acids and pharmacological compounds.7 Lignocellulosic materials are sensitive to irradiation in the range from 764 Ruggiero et al. J. Braz. Chem. Soc. 300 to 400 nm a...

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“…26 The 1 H and 13 C NMR spectra of compound 1 confirm its structure. 26 The synthesis of 3 (Scheme 1) needed the preparation of 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl radical.…”

Section: Synthesis Of 1 and 3 Derivativesmentioning

confidence: 76%

Section: Synthesis Of 1 and 3 Derivativesmentioning

confidence: 76%

Section: Photocoloration Of Fibers After Grafting Of Uv-absorber And/mentioning

confidence: 99%

Section: Grafting Of 1 and 3 Derivatives Onto Bagasse Fibersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photodegradation of sugarcane bagasse fibers: influence of acetylation or grafting UV-absorber and/or hindered nitroxide radical on their photostability

Ruggiero

Machado

Hoareau

et al. 2006

J. Braz. Chem. Soc.

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Polyester binders for wood containing benzotriazole and HALS light stabilizers

Sundell

Sundholm

2004

J of Applied Polymer Sci

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Three new polyester binders containing either benzotriazole-type or hindered amine light stabilizers (HALS)-type light stabilizers were synthesized. The binders were characterized by 13 C and 1 H NMR, FTIR, UV-VIS spectroscopy, and size exclusion chromatography. It was found that it was possible to bind a benzotriazole-type light stabilizer to the polymer backbone of the binder if a suitable group was present in the stabilizer. However, there was no proof that the HALS-type stabilizer was bound to the binder. The average penetration depth of the binders into the radial surface of pine wood was mainly below 480 m into earlywood and below 2500 m into latewood. The average penetration depth into the tangential surface was around 1000 m in the earlywood and around 2500 m in the latewood. Artificial weathering causes a binder-treated wood surface to darken independently of the binder used. The yellowness of the irradiated pine samples increased at the beginning of the exposure but decreased during longer exposure times. The benzotriazole stabilizer, Tinuvin 213, protected the surface of wood quite well; the other stabilizers were poor. The wood surface became rougher in appearance, cracks along the microfibril orientation became pronounced, and the bordered pits were degraded in the weathered samples.

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Improvement of the durability of clear coatings by grafting of UV-absorbers on to wood

Kiguchi

Evans

Ekstedt

et al. 2001

Surface Coatings International Part B: Coatings Transactions

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Attempt to Protect Wood Colour Against UV/Visible Light by Using Antioxidants Bearing Isocyanate Groups and Grafted to the Material with Microwave

Cited by 31 publications

References 13 publications

Photodegradation of sugarcane bagasse fibers: influence of acetylation or grafting UV-absorber and/or hindered nitroxide radical on their photostability

Photodegradation of sugarcane bagasse fibers: influence of acetylation or grafting UV-absorber and/or hindered nitroxide radical on their photostability

Polyester binders for wood containing benzotriazole and HALS light stabilizers

Improvement of the durability of clear coatings by grafting of UV-absorbers on to wood

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